The present invention relates generally to an improved agricultural disc mower, and particularly to an improved cutterhead for a disc mower that permits quick and easy replacement of the knife without the necessity of removing and installing nuts and bolts.
For several years agricultural and most roadside mowing, whether by itself or as one step in a crop treatment process, has been changing from the older sickle mowers to disc mowers. Typical disc cutterbars include an elongated housing containing a train of meshed idler and drive spur gears, or a main power shaft coupled by respective bevel gear sets, for delivering power to respective drive shafts for cutterheads spaced along the length of the cutterbar. The cutterheads each comprise a cutting disc including diametrically opposed cutting blades and having a hub coupled to an upper end of a drive shaft, the lower end of the drive shaft carrying a spur gear in the case where a train of meshed spur gears is used for delivering power, and carrying a bevel gear of a given one of the bevel gear sets in the case where a main power shaft is used. In either case, bearings are used to support the various shafts. The cutterheads are rotated at a relatively fast speed making durability a necessary characteristic of all components. For background information on the structure and operation of some typical disc cutterbars, reference is made to U.S. Pat. No. 4,815,262, issued to E. E. Koch and F. F. Voler, the descriptive portions thereof being incorporated herein in full by reference.
Operators and maintenance personnel are required, from time to time, to remove and replace a knife or knives on disc cutterbars. This process typically requires the removal of nuts, bolts, washers, spacers and other miscellaneous hardware in a difficult working environment. The parts of the cutterhead are usually covered with crop chaff and dirt, and the entire machine is often in a hot field with bugs. It would be very helpful to provide these personnel with a simpler knife-holding arrangement that can be changed with minimum effort and time.
Accordingly, it is an object of the present invention overcome the problems identified above.
It is another object of the present invention to provide a quick change system for the knives of a disc cutterhead.
Another object of the present invention is to provide a disc cutterhead that requires no wrenches to replace the knives.
It is another object of the instant invention to provide a knife mounting system for a rotary cutterhead that employs a spring mechanism to hold the knife blade in position for ease of replacement.
It is still another object of the instant invention to provide a knife mounting system for a rotary cutterhead that uses a spring plate bolted to an upper mount, the spring plate and upper mount clamped together by way of a knife bolt. Thus, the knife is held securely between the spring plate and the upper mount.
It is yet another object of this invention to provide a tool to loosen the knife by forcing the spring plate down to free the knife.
It is a still further object of this invention to provide a quick change disc knife mounting mechanism and tool that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple, versatile and effective in use.
These and other objects are attained by providing a rotary disc cutterhead knife mounting system that uses a spring plate bolted to the underside of the cutterhead cover. A knife pin is attached also to the underside of the cover, adjacent the outer edge thereof, and extends downwardly therefrom. The knife has a mounting hole therethrough, slightly larger that the diameter of the knife pin. With the knife hole fitted on the knife pin, the spring plate compresses the knife toward the underside of the cover; holding the knife in operating position. A special tool is used to remove the knife by forcing the spring plate downward, freeing the knife.